Optical film for reducing color shift and organic light-emitting display device employing the same

ABSTRACT

Optical films, and organic light-emitting display devices employing the same, include a high refractive index pattern layer including a lens pattern region and a non-pattern region alternately formed, wherein the lens pattern region includes a plurality of grooves each having a depth larger than a width thereof, and the non-pattern region has no pattern; and a low refractive index pattern layer formed of a material having a refractive index smaller than a refractive index of the high refractive index pattern layer, wherein the low refractive index pattern includes a plurality of filling portions filling the plurality of grooves.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/158,287, filed on Jan. 17, 2014, which claims priority to KoreanApplication No. 10-2013-0064338 filed on Jun. 4, 2013, the entirecontents of each of which are hereby incorporated by reference.

BACKGROUND

1. Field

The present disclosure relates to optical films for reducing color shiftand/or organic light-emitting display devices employing the same.

2. Description of the Related Art

Organic light-emitting diodes (OLEDs) include an anode, an organiclight-emitting layer, and a cathode. Here, when a voltage is appliedbetween the anode and the cathode, holes are injected into the organiclight-emitting layer from the anode, and electrons are injected into theorganic light-emitting layer from the cathode. At this time, the holesand the electrons, which are injected into the organic light-emittinglayer, are recombined in the organic light-emitting layer so as togenerate excitons, and the excitons emit light while transitioning froman excited state to a ground state.

In such an OLED, a lifespan problem resulting from deterioration due toa luminescent material, which is an organic material, is key indeveloping OLED technology, and many techniques have been introduce toovercome this problem.

A technique using a microcavity structure, which is one of thetechniques to overcome the lifespan problem, causes light that is beingemitted and has a specific wavelength to resonate, so as to increase theintensity of the light and emit the light to the outside. That is, inthe technique, a distance between an anode and a cathode is designed tomatch with a representative wavelength of each of red (R), green (G),and blue (B), so that only a corresponding light beam resonates and isemitted to the outside and other light beams are attenuated. As aresult, in the technique, the intensity of the light beam emitted to theoutside is increased and sharpened, thereby increasing brightness andcolor purity. In addition, the increase in brightness induces low powerconsumption, thereby increasing a lifespan of the OLED.

However, in a microcavity structure, wavelengths to be amplified aredetermined based on a thickness of an organic deposition material layer.Here, a length of a light path changes at lateral sides, thereby causingan effect similar to a change in the thickness of an organic depositionmaterial layer. Therefore, wavelengths to be amplified are changed.

In other words, as the viewing angle is tilted from the front to a side,the maximum resolution wavelength becomes shorter, and thus a colorshift occurs as the maximum resolution wavelength decreases. Forexample, even if white color is embodied at the front, the white colormay become bluish at a lateral side due to blue shift phenomenon.

SUMMARY

Provided are optical films for reducing color shift and/or organiclight-emitting display devices employing the same.

According to some example embodiments, an optical film includes a highrefractive index pattern layer including a lens pattern region and anon-pattern region alternately formed, wherein the lens pattern regionincludes a plurality of grooves each having a depth larger than a widththereof, and the non-pattern region has no pattern; and a low refractiveindex pattern layer formed of a material having a refractive indexsmaller than a refractive index of the high refractive index patternlayer, wherein the low refractive index pattern includes a plurality offilling portions filling the plurality of grooves.

The plurality of grooves may be engraved in the lens pattern region.

The lens pattern region may have a width larger than a width of thenon-pattern region.

The low refractive index pattern layer may further include a flat filmhaving a set thickness, and the flat film connects the plurality offilling portions.

The low refractive index pattern layer may be formed of a resinmaterial.

The low refractive index pattern layer may be formed of a transparentresin material containing a light diffuser or a light absorber.

The plurality of grooves may each have an extended stripe shape.

The plurality of grooves may have a dot shape in a perspective view withrespect to the high refractive index pattern layer, and a parabolicshape in a cross-sectional view shape with respect to the highrefractive index pattern layer.

The optical film may be attached to a display panel having anarrangement of pixels, the arrangement of pixels including an emissionregion and a non-emission region alternately formed, wherein the lenspattern region faces the emission region, and wherein the lens patternregion and the non-pattern region are arranged so that the non-patternregion faces at least a part of the non-emission region.

The lens pattern region may have a width larger than a width of theemission region.

The optical film may further include an anti-reflection film on the highrefractive index pattern layer; and a first adhesive layer under the lowrefractive index pattern layer.

A first base layer may be between the high refractive index patternlayer and the anti-reflection film.

The optical film may further include a circular polarization filmincluding a phase shift layer and a linear polarization layer.

The first adhesive layer, the low refractive index pattern layer, thehigh refractive index pattern layer, the phase shift layer, the linearpolarization layer, the first base layer and the anti-reflection filmmay be sequentially arranged.

The optical film may further include a second base layer and a secondadhesive layer, wherein the high refractive index pattern layer, thesecond base layer, the second adhesive layer and the phase shift layerare sequentially arranged.

The first adhesive layer, the phase shift layer, the linear polarizationlayer, the low refractive index pattern layer, the high refractive indexpattern layer, the first base layer and the anti-reflection film may besequentially arranged.

The optical film may further include a second base layer and a secondadhesive layer, wherein the linear polarization layer, the second baselayer, the second adhesive layer and the low refractive index patternlayer are sequentially arranged.

The first adhesive layer, the phase shift layer, the low refractiveindex pattern layer, the high refractive index pattern layer, the linearpolarization layer, the first base layer and the anti-reflection filmmay be sequentially arranged.

The optical film may further include a second base layer between thehigh refractive index pattern layer and the linear polarization layer.

The optical film may further include a phase shift layer, a linearpolarization layer, and a first base layer, wherein the first adhesivelayer, the phase shift layer, the linear polarization layer, the firstbase layer and the low refractive index pattern layer are sequentiallyarranged.

The optical film may further include a transmittance adjusting layerbetween the high refractive index pattern layer and the anti-reflectionfilm.

The optical film may further include a first carrier film between thehigh refractive index pattern layer and the transmittance adjustinglayer.

The optical film may further include a second adhesive layer between thefirst carrier film and the transmittance adjusting layer, and a secondcarrier film between the transmittance adjusting layer and theanti-reflection film.

The optical film may further include a first carrier film between thetransmittance adjusting layer and the anti-reflection film.

The optical film may further include a second adhesive layer between thehigh refractive index pattern layer and the transmittance adjustinglayer, and a second carrier film between the first adhesive layer andthe low refractive index pattern layer.

According to other example embodiments, an organic light-emittingdisplay device includes an organic light-emitting display panelincluding a plurality of pixels and an organic light-emitting layer,wherein the plurality of pixels each emit light beams having differentwavelengths, and the organic light-emitting layer has a microcavitystructure configured to resonate and emit a light beam of acorresponding wavelength; and the optical film on the organiclight-emitting display panel.

The plurality of grooves may each have an extended stripe shape.

The optical film may be arranged on the organic light-emitting displaypanel in such a manner that a longitudinal direction of the extendedstripe shape is in a vertical direction of the organic light-emittingdisplay panel.

A width of the non-pattern region of the optical film in a horizontaldirection may be smaller than a distance between the plurality of pixelsseparated from each other in the horizontal direction.

A ratio of an area of the lens pattern region in the optical film may begreater than an aperture ratio of the organic light-emitting displaypanel.

The organic light-emitting display device may further include a firstadhesive layer between the organic light-emitting display panel and thelow refractive index pattern layer; and an anti-reflection film on thehigh refractive index pattern layer.

A circular polarization film including a phase shift layer and a linearpolarization layer may be between the high refractive index patternlayer and the anti-reflection film.

The organic light-emitting display device may further include atransmittance adjusting layer between the high refractive index patternlayer and the anti-reflection film.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings. FIGS. 1-23 represent non-limiting, example embodiments asdescribed herein.

FIG. 1 is a cross-sectional view illustrating a schematic structure ofan optical film according to some example embodiments of the presentdisclosure;

FIG. 2 is an exploded perspective view illustrating a detailed shape ofa lens pattern region in the optical film of FIG. 1;

FIG. 3 illustrates a light path through which light is perpendicularlyincident on the lens pattern region of the optical film of FIG. 1;

FIG. 4 illustrates a light path through which light is obliquelyincident on the lens pattern region of the optical film of FIG. 1;

FIG. 5 is a conceptual diagram in which image blur may occur in adisplay panel including an optical film according to a comparativeexample;

FIG. 6 is an exploded perspective view illustrating a schematicstructure of an optical film according to other example embodiments ofthe present disclosure;

FIG. 7 is an exploded perspective view illustrating a schematicstructure of an optical film according to still other exampleembodiments of the present disclosure;

FIG. 8 is a perspective view illustrating a schematic structure of anoptical film according to further example embodiments of the presentdisclosure;

FIG. 9 is a cross-sectional view illustrating a schematic structure ofan optical film according to yet other example embodiments of thepresent disclosure;

FIGS. 10 to 16 are examples employing a circular polarization film andare cross-sectional views illustrating schematic structures of opticalfilms according to various example embodiments of the presentdisclosure;

FIGS. 17 to 20 are examples employing a transmittance adjusting layerand are cross-sectional views illustrating schematic structures ofoptical films according to various example embodiments of the presentdisclosure;

FIG. 21 is a cross-sectional view illustrating a schematic structure ofan organic light-emitting display device according to exampleembodiments of the present disclosure;

FIG. 22 is a schematic diagram illustrating an arrangement relationshipbetween an optical film and pixels in the organic light-emitting displaydevice of FIG. 21; and

FIG. 23 is a simulation graph illustrating image blur (blur intensity)and color shift Δu′v′ according to S2/S1.

DETAILED DESCRIPTION

Various example embodiments will now be described more fully withreference to the accompanying drawings in which some example embodimentsare shown. However, specific structural and functional details disclosedherein are merely representative for purposes of describing exampleembodiments. Thus, the invention may be embodied in many alternate formsand should not be construed as limited to only example embodiments setforth herein. Therefore, it should be understood that there is no intentto limit example embodiments to the particular forms disclosed, but onthe contrary, example embodiments are to cover all modifications,equivalents, and alternatives falling within the scope.

In the drawings, the thicknesses of layers and regions may beexaggerated for clarity, and like numbers refer to like elementsthroughout the description of the figures.

Although the terms first, second, etc. may be used herein to describevarious elements, these elements should not be limited by these terms.These terms are only used to distinguish one element from another. Forexample, a first element could be termed a second element, and,similarly, a second element could be termed a first element, withoutdeparting from the scope of example embodiments. As used herein, theterm “and/or” includes any and all combinations of one or more of theassociated listed items.

It will be understood that, if an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected, or coupled, to the other element or intervening elements maybe present. In contrast, if an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.).

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of exampleembodiments. As used herein, the singular forms “a,” “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises,” “comprising,” “includes” and/or “including,” if usedherein, specify the presence of stated features, integers, steps,operations, elements and/or components, but do not preclude the presenceor addition of one or more other features, integers, steps, operations,elements, components and/or groups thereof.

Spatially relative terms (e.g., “beneath,” “below,” “lower,” “above,”“upper” and the like) may be used herein for ease of description todescribe one element or a relationship between a feature and anotherelement or feature as illustrated in the figures. It will be understoodthat the spatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, for example, the term “below” can encompass both anorientation that is above, as well as, below. The device may beotherwise oriented (rotated 90 degrees or viewed or referenced at otherorientations) and the spatially relative descriptors used herein shouldbe interpreted accordingly.

Example embodiments are described herein with reference tocross-sectional illustrations that are schematic illustrations ofidealized embodiments (and intermediate structures). As such, variationsfrom the shapes of the illustrations as a result, for example, ofmanufacturing techniques and/or tolerances, may be expected. Thus,example embodiments should not be construed as limited to the particularshapes of regions illustrated herein but may include deviations inshapes that result, for example, from manufacturing. For example, animplanted region illustrated as a rectangle may have rounded or curvedfeatures and/or a gradient (e.g., of implant concentration) at its edgesrather than an abrupt change from an implanted region to a non-implantedregion. Likewise, a buried region formed by implantation may result insome implantation in the region between the buried region and thesurface through which the implantation may take place. Thus, the regionsillustrated in the figures are schematic in nature and their shapes donot necessarily illustrate the actual shape of a region of a device anddo not limit the scope.

It should also be noted that in some alternative implementations, thefunctions/acts noted may occur out of the order noted in the figures.For example, two figures shown in succession may in fact be executedsubstantially concurrently or may sometimes be executed in the reverseorder, depending upon the functionality/acts involved.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which example embodiments belong. Itwill be further understood that terms, such as those defined in commonlyused dictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

In order to more specifically describe example embodiments, variousfeatures will be described in detail with reference to the attacheddrawings. However, example embodiments described are not limitedthereto.

FIG. 1 is a cross-sectional view illustrating a schematic structure ofan optical film according to some example embodiments of the presentdisclosure. FIG. 2 is an exploded perspective view illustrating adetailed shape of a lens pattern region in the optical film 1 of FIG. 1.

Referring to FIGS. 1 and 2, an optical film 1 includes a high refractiveindex pattern layer 110 and a low refractive index pattern layer 120. Inthe high refractive index pattern layer 110, the lens pattern region A1in which a plurality of grooves GR, which each has a depth that islarger than a width thereof, are formed (or, engraved) and a non-patternregion A2 having no pattern are alternately formed. The low refractiveindex pattern layer 120 is formed of a material having a refractiveindex that is smaller than that of the high refractive index patternlayer 110, and includes a plurality of filling portions P that fill theplurality of grooves GR.

The grooves GR may be formed using techniques known in the art. Forexample, a high refractive index layer (not shown) may be etched usingphotolithography techniques, wet or dry chemical mechanical polishing orsimilar techniques.

The high refractive index pattern layer 110 is formed of a materialhaving a refractive index that is greater than 1 (e.g., a transparentplastic material). In addition, the high refractive index pattern layer110 may be formed of a transparent plastic material including a lightdiffuser or a light absorber. Diffusion beads may be used as the lightdiffuser, and a black dye, such as carbon black, may be used as thelight absorber. The light diffuser improves a psycho-visualcharacteristic by planarizing peaks that may occur in a color shiftgraph or a luminance profile according to viewing angles. In addition,the light absorber may contribute to improving characteristics, such asa contrast ratio or color purity, by using a dye that selectivelyabsorbs a specific wavelength or carbon black that may absorb allwavelengths of a visible ray.

The groove GR may be formed to have an aspect ratio that is greater than1 (i.e., the groove GR may be formed to have a depth d that is greaterthan a width w), and may be repeatedly disposed with a set (or,predetermined) period T1.

A surface of the groove GR may be a curved surface or an asphericalsurface. For example, the curved surface of the groove GR may be anellipsoid, a paraboloid, or a hyperboloid. In addition, the groove GRmay have an extended stripe shape (or, extend along the z-axis) asillustrated in FIG. 2.

As illustrated in FIG. 2, the low refractive index pattern layer 120 maybe formed as a flat film having a set (or, predetermined) thicknesswhich connects filling portions that fill the grooves GR. The thicknessand flatness of a flat_portion may vary according to a filling materialto be filled into the grooves GR or a filling method. In addition, thelow refractive index pattern layer 120 is formed of a material having arefractive index that is smaller than that of the high refractive indexpattern layer 110. The low refractive index pattern layer 120 may beformed of a transparent plastic material, or a transparent plasticmaterial including a light diffuser or a light absorber. Diffusion beadsmay be used as the light diffuser, and a black dye, such as carbonblack, may be used as the light absorber.

The lens pattern region A1 and the non-pattern region A2 may bealternately disposed within a set (or, predetermined) period T2. The set(or, predetermined) period T2, the width of the lens pattern region A1,and the width of the non-pattern region A2 may be determined inconsideration of the arrangement of pixels of a display panel to whichthe optical film 1 is attached. The optical film 1 may be attached tothe display panel having the arrangement of pixels in which an emissionregion and a non-emission region are alternately disposed. The widths ofthe lens pattern region A1 and the non-pattern region A2 and the set (orpredetermined) period T2 may be determined so that the lens patternregion is disposed to face the emission region and that the non-patternregion is disposed to face at least a part of the non-emission region.An arrangement relationship between the optical film 1 and the displaypanel will be described below with reference to FIGS. 21 and 22.

The lens pattern region A1 of the optical film 1 refracts light, whichis incident from one direction, in various directions according to itsincidence position, and emits and mixes the light. On the other hand,the non-pattern region A2 is a region where such a function of the lenspattern region A1 is not performed. The non-pattern region A2 isappropriately disposed between the lens pattern regions A1, therebyallowing image blur to be reduced.

First, the function of the lens pattern region A1 will be describedbelow with reference to FIGS. 3 and 4.

FIG. 3 illustrates a light path through which light is perpendicularlyincident on the lens pattern region of the optical film of FIG. 1. FIG.4 illustrates a light path through which light is obliquely incident onthe lens pattern region of the optical film of FIG. 1. For convenienceof description, the optical film is shown to include only the lenspattern region.

Referring to FIGS. 3 and 4, an interface between the high refractiveindex pattern layer 110 and the low refractive index pattern layer 120includes curved surfaces 110 a and flat surfaces 110 b which constitutethe grooves GR. The curved surface 110 a serves as a lens surface.

Referring to FIG. 3, the light that is perpendicularly incident on theoptical film 1 is refracted in different directions according topositions at which the light encounters the curved surface 110 a, and isemitted from the optical film 1. That is, because light beams having thesame incidence angle are refracted in various directions according topositions at which the light beams encounter the curved surface 110 a,there is an effect of light diffusion.

In addition, referring to FIG. 4, the light that is obliquely incidenton the optical film 1 is refracted in different directions according topositions on which the light is incident. Specifically, a light beam L1,which encounters the curved surface 110 a in the high refractive indexpattern layer 110 via the flat surface 110 b, is totally reflected fromthe curved surface 110 a, and is emitted from the optical film 1. Inthis path, an angle at which the light is emitted from the top surfaceof the high refractive index pattern layer 110 is smaller than that atwhich the light is incident on the optical film 1. On the other hand, alight beam L2 passing through the flat surface 110 b without passingthrough the curved surface 110 a is refracted in such a manner that arefraction angle of the light beam L2 is greater than an incidence anglethereof at an interface between the high refractive index pattern layer110 and the outside, and thus the light beam L2 is emitted from theoptical film 1 with an angle greater than an angle at which the lightbeam L2 is incident on the optical film 1. In addition, light thatencounters the curved surface 110 a in the low refractive index patternlayer 120 is refracted on the curved surface 110 a and is then refractedagain on the top surface of the high refractive index pattern layer 110,and thus the light is emitted from the optical film 1 at a refractionangle greater than that of the light beam L2 that is emitted via theflat surface 110 b without encountering the curved surface 110 a. Inthis manner, the light beams L1, L2, and L3 that are obliquely incidenton the optical film 1 at the same angle are emitted from the opticalfilm 1 at different refraction angles according to positions on whichthe light beams L1, L2, and L3 are incident.

As described above, the light passing through the optical film 1 is acombination of light beams that are incident on the optical film 1 atvarious angles.

In the above description, the detailed light path through whichincidence light is diffused is just an example. The light path slightlyvaries according to the difference in the refractive index between thehigh refractive index pattern layer 110 and the low refractive indexpattern layer 120, the aspect ratio of the groove GR in the highrefractive index pattern layer 110, the period T1 with which the groovesGR are repeatedly disposed, the width w of the groove GR, the shape ofthe curved surface of the groove GR, or the like, and thus the degree towhich light beams are combined or the brightness of the emitted lightvaries.

The above-described light mixing effect allows, when light incident onthe optical film 1 has different optical characteristics according toincidence angles thereof, the light to equally mix the opticalcharacteristics and to be emitted. For example, when light is emittedfrom an organic light-emitting diode (OLED), a color shift phenomenon isshown in which the light has different color characteristics accordingto emission angles thereof. Because the degrees of color shift are mixedafter the light passes through the optical film 1 having theabove-described structure, the degree of color shift according toviewing angles is reduced.

As described above, the lens pattern region of optical film 1 has a goodfunction for reducing color shift, but which results in image blur.

FIG. 5 is a conceptual diagram in which image blur may occur in adisplay panel including an optical film according to a comparativeexample.

Unlike the structure of FIG. 1 in which the lens pattern region and thenon-pattern region are alternately disposed, an optical film 1′according to the comparative example is configured as the lens patternregion as a whole.

That is, the optical film 1′ includes a high refractive index patternlayer 110′ in which a plurality of grooves are formed, and a lowrefractive index pattern layer 120′ including filling portions that fillthe grooves. The plurality of grooves are uniformly formed in the highrefractive index pattern layer 110′.

The optical film 1′ is any of various types of films including a basematerial or an anti-reflection film. The optical film 1′ and a base filmBF are attached onto a display panel DP.

The display panel DP includes a plurality of pixels PX that are formedso as to be separated from each other at set (or predetermined)intervals. The pixel PX is an emission region, and a region between thepixels PX is a non-emission region. A ratio of the emission region inthe display panel DP is referred to as an aperture ratio. Because thereis a limitation in reducing an area of a wiring line or a TFT, theaperture ratio is decreased as the pixel PX is reduced in size, that is,as a resolution becomes high.

In this manner, when the area of the non-emission region is large, theoptical film 1′ that is disposed to correspond to the non-emissionregion causes image blur and a ghost image, which results in a reductionin image quality.

In FIG. 5, a solid line represents a light path in a case that theoptical film 1′ is present, and a dotted line represents a case where itis assumed that the optical film 1′ is not present. When the opticalfilm 1′ is not present, light that is incident on a positioncorresponding to an upper portion of the non-emission region or an upperportion of the adjacent pixel from the pixels PX is refracted andreflected on a top surface of the base film BF and is then directed to aposition that is out of a viewer's sight. However, when the optical film1′ is present, light reaches the viewer's eyes by passing through thebase film BF along the same light path as the solid line by the actionof a lens pattern, and the light causes image blur.

The image blur may be reduced by reducing a distance between the pixelPX and the optical film 1′, but there is a limitation in reducing thedistance because a glass substrate GL that is generally used as asubstrate of the display panel DP has a thickness of about 630 to about1100 μm.

In the optical film of the current example embodiments, the non-patternregion is introduced to the position corresponding to the non-emissionregion between the pixels so as to reduce image blur.

FIG. 6 is a perspective view illustrating a schematic structure of anoptical film according to other example embodiments of the presentdisclosure.

Similarly to the optical film 1 of FIG. 1, an optical film 2 includes alens pattern region and a non-pattern region. For convenience ofdescription, the optical film 2 is shown to include only the lenspattern region.

The optical film 2 includes the high refractive index pattern layer 110in which the plurality of grooves GR each constituted by a curvedsurface are formed or engraved, and a low refractive index pattern layer121. The groove GR is formed to have a depth that is greater than awidth thereof. The high refractive index pattern layer 110 is formed ofa material having a refractive index that is greater than 1. The lowrefractive index pattern layer 121 is formed of a material having arefractive index that is lower than the refractive index of the highrefractive index pattern layer 110. The optical film 2 of the currentexample embodiments is different from the optical film 1 of the previousexample embodiments in terms of the shape of the low refractive indexpattern layer 121. That is, as compared with the optical film 1 of FIG.1, the low refractive index pattern layer 121 does not have a shapeincluding a flat film connecting filling portions that fill the groovesGR, and is constituted by only the filing portions filled in the groovesGR. The filling portions that fill the grooves GR may be formed of aresin material or may be air.

FIG. 7 is an exploded perspective view illustrating a schematicstructure of an optical film according to still other exampleembodiments of the present disclosure.

Similarly to the optical film 1 of FIG. 1, the optical film 3 includes alens pattern region and a non-pattern region. For convenience ofdescription, the optical film 3 is shown to include only the lenspattern region.

The optical film 3 includes a high refractive index pattern layer 210having a pattern in which the plurality of grooves GR each constitutedby a curved surface are formed or engraved, and a low refractive indexpattern layer 220 that is formed on the high refractive index patternlayer 210. The low refractive index pattern layer 220 is formed of amaterial having a refractive index that is lower than a refractive indexof the high refractive index pattern layer 210, and includes fillingportions P that fill the plurality of grooves GR.

The optical film 3 of the current example embodiments is different fromthe optical film 1 of FIG. 1 in that the groove GR has a dot (or,conical) shape.

FIG. 8 is a perspective view illustrating a schematic structure of anoptical film according to further example embodiments of the presentdisclosure.

Similarly to the optical film 1 of FIG. 1, the optical film 4 includes alens pattern region and a non-pattern region. For convenience ofdescription, the optical film 4 is shown to include only the lenspattern region.

The optical film 4 of the current example embodiments is different fromthe optical film 3 of FIG. 7 in terms of the shape of a low refractiveindex pattern layer 121. The low refractive index pattern layer 121 doesnot include a flat film connecting filling portions that fill thegrooves GR, and is constituted by only the filling portions that fillthe grooves GR. The filling portions that fill the grooves GR may beformed of a resin material or may be air or another gaseous medium.

The above-described optical films 1 through 4 may further include anadhesive layer, an anti-reflection film, a circular polarization film, atransmittance adjusting layer, or the like, which is necessary when theoptical films 1 through 4 are applied to an organic light-emittingdisplay device. Hereinafter, structures of optical films according tovarious example embodiments will be described in detail.

FIG. 9 is a cross-sectional view illustrating a schematic structure ofan optical film according to yet other example embodiments of thepresent disclosure.

Referring to FIG. 9, an optical film 5 further includes ananti-reflection film 190 that is formed above the high refractive indexpattern layer 110, and a first adhesive layer 131 that is formed underthe low refractive index pattern layer 120. In addition, a first baselayer 141 may further be formed between the high refractive indexpattern layer 110 and the anti-reflection film 190.

The anti-reflection film 190 may have a multi-layered structure in whichinorganic materials having different refractive indexes are stacked, forexample, a two-layered structure including a high refractive index layerand a low refractive index layer.

The first adhesive layer 131, which is provided for adhesion with anorganic light-emitting display panel, may be formed of a pressuresensitive adhesive (PSA) or may be formed of a PSA including a lightabsorber or a light diffuser. In addition, the high refractive indexpattern layer 110 and/or the low refractive index pattern layer 120 maybe formed of a transparent material containing a light absorber. When amaterial containing a light absorber is applied to various layersconstituting an optical film, reflectivity of external light isdecreased, thereby improving visibility.

The first base layer 141 is used as a base material for forming the highrefractive index pattern layer 110 and the low refractive index patternlayer 120. The first base layer 141 may be formed of an opticalisotropic material, for example, triacetyl cellulose (TAC).

FIGS. 10 to 16 are examples employing a circular polarization film andare cross-sectional views illustrating schematic structures of opticalfilms according to various example embodiments of the presentdisclosure.

The circular polarization film may include a phase shift layer 150 and alinear polarization layer 160.

The linear polarization layer 160 may include a polyvinyl alcohol (PVA)film. Alternatively, the linear polarization layer 160 may have astructure in which the PVA film and a TAC film are stacked on eachother, or may have various structures. The PVA film is a film thatpolarizes light, and may be formed by adsorbing a dichromatic pigment toPVA, which is a polymer material.

Referring to FIGS. 10 and 11, optical films 6 and 7 include the firstadhesive layer 131, the low refractive index pattern layer 120, the highrefractive index pattern layer 110, the phase shift layer 150, thelinear polarization layer 160, the first base layer 141, and theanti-reflection film 190, which are sequentially disposed from thebottom.

The circular polarization film, including the phase shift layer 150 andthe linear polarization layer 160, increases visibility of image formedby organic light-emitting display panel (not shown) by decreasingreflectivity of external light. When unpolarized external light isincident, the external light is changed to linearly polarized lightwhile passing through the linear polarization layer 160, and is thenchanged to circularly polarized light by the phase shift layer 150. Thecircularly polarized light passes through the interface between thephase shift layer 150 and the high refractive index pattern layer 110,the high refractive index pattern layer 110, the low refractive indexpattern layer 120, and the first adhesive layer 131, is reflected fromthe interface between the first adhesive layer 131 and the organiclight-emitting display panel (not shown), and is then changed tocircularly polarized light that rotates in an opposite direction. Thecircularly polarized light is changed to linearly polarized light thatis perpendicular to a transmission axis of the linear polarization layer160 while passing through the phase shift layer 150, and thus is notemitted to the outside.

As shown in FIGS. 10 and 11, the circular polarization film is disposedon the high refractive index pattern layer 110, and thus when the highrefractive index pattern layer 110 is formed of an anisotropic materialhaving a different optical axis from the circular polarization film, thepolarization is broken. Thus, the incident external light may be emittedto the outside again, and the amount of reflectivity thereof may berapidly increased, thereby decreasing visibility. Therefore, the highrefractive index pattern layer 110 is required to be formed of anisotropic material having the same optical axis as the circularpolarization film, for example, TAC or polycarbonate (PC) formed bysolvent casting.

As compared with the optical film 6 of FIG. 10, the optical film 7 ofFIG. 11 further includes a second base layer 142 and a second adhesivelayer 132 between the high refractive index pattern layer 110 and thephase shift layer 150, which are disposed in this order toward the phaseshift layer 150 from the high refractive index pattern layer 110.

Referring to FIGS. 12 and 13, optical films 8 and 9 include the firstadhesive layer 131, the phase shift layer 150, the linear polarizationlayer 160, the low refractive index pattern layer 120, the highrefractive index pattern layer 110, the first base layer 141, and theanti-reflection film 190.

The optical film 9 of FIG. 13 further includes the second base layer 142and the second adhesive layer 132 between the linear polarization layer160 and the low refractive index pattern layer 120, which are disposedin this order toward the linear polarization layer 160 and the lowrefractive index pattern layer 120.

Referring to FIGS. 14 and 15, optical films 10 and 11 include the firstadhesive layer 131, the phase shift layer 150, the low refractive indexpattern layer 120, the high refractive index pattern layer 110, thelinear polarization layer 160, the first base layer 141, and theanti-reflection film 190, which are sequentially disposed from thebottom.

The optical film 11 of FIG. 15 further includes the second base layer142 between the high refractive index pattern layer 110 and the linearpolarization layer 160.

An optical film 12 of FIG. 16 includes the first adhesive layer 131, thephase shift layer 150, the linear polarization layer 160, the first baselayer 141, the low refractive index pattern layer 120, the highrefractive index pattern layer 110, and the anti-reflection film 190,which are sequentially disposed from the bottom.

FIGS. 17 through 20 are examples employing a transmittance adjustinglayer and are cross-sectional views illustrating schematic structures ofoptical films according to various example embodiments of the presentdisclosure.

The transmittance adjusting layer 170 may be a film that is formed bydiffusing a black dye, a pigment, carbon black, or cross-linkedparticles whose surfaces are coated with those materials, in a highmolecular resin. The high molecular resin may be a binder, such aspolymethyl methacrylate (PMMA) or a ultra-violet (UV)-curing resin, suchas an acryl-based resin. However, the present disclosure is not limitedthereto. In addition, the thickness of the transmittance adjusting layer170 or the amount of a black material contained in the high molecularresin may be appropriately determined according to optical properties ofthe black material. The transmittance of the transmittance adjustinglayer 170 may be equal to or greater than 40%, which is higher than thetransmittance of the circular polarization film. The transmittanceadjusting layer 170 is used to compensate for a disadvantage of thecircular polarization film that almost perfectly blocks external lightbut has a low transmittance.

Referring to FIGS. 17 and 18, optical films 13 and 14 include the firstadhesive layer 131, the low refractive index pattern layer 120, the highrefractive index pattern layer 110, a first carrier film 181, thetransmittance adjusting layer 170 and the anti-reflection film 190,which are sequentially disposed from the bottom.

The optical film 14 of FIG. 18 further includes the second adhesivelayer 132 that is formed between the first carrier film 181 and thetransmittance adjusting layer 170, and a second carrier film 182 that isformed between the transmittance adjusting layer 170 and theanti-reflection film 190.

Optical films 15 and 16 of FIGS. 19 and 20 include the first adhesivelayer 131, the low refractive index pattern layer 120, the highrefractive index pattern layer 110, the transmittance adjusting layer170, the first carrier film 181, and the anti-reflection film 190, whichare sequentially disposed from the bottom.

The optical film 16 of FIG. 20 further includes the second adhesivelayer 132 that is formed between the high refractive index pattern layer110 and the transmittance adjusting layer 170, and the second carrierfilm 182 that is formed between the first adhesive layer 131 and the lowrefractive index pattern layer 120.

The first and second carrier films 181 and 182 are used as basematerials for forming the high refractive index pattern layer 110 andthe low refractive index pattern layer 120, or base materials forforming the anti-reflection film 190 or the transmittance adjustinglayer 170. Because optical films 13 through 16 of FIGS. 17 through 20 donot include a linear polarization layer, the optical films 13 through 16do not need a function of maintaining polarization. Thus, the opticalfilms 13 through 16 may be formed of various materials including TAC,PET, PC, or the like as a base material.

In the optical films 5 through 16 of FIGS. 9 through 20, the highrefractive index pattern layer 110 and the low refractive index patternlayer 120 have shapes shown in FIG. 2. However, the present disclosureis not limited thereto, and the high refractive index pattern layer 110and the low refractive index pattern layer 120 may have shapes shown inFIGS. 6 through 8.

FIG. 21 is a cross-sectional view illustrating a schematic structure ofan organic light-emitting display device according to exampleembodiments of the present disclosure, and FIG. 22 is a schematicdiagram illustrating an arrangement relationship between an optical filmand pixels of an organic light-emitting display panel in the organiclight-emitting display device of FIG. 21.

The organic light-emitting display device 500 emits light beams havingdifferent wavelengths, and includes the organic light-emitting displaypanel 510 and the optical film 520. The organic light-emitting displaypanel 510 includes a plurality of pixels each including an organiclight-emitting layer that has a microcavity structure configured toproduce (or, causing) a resonance phenomenon with respect to the lightbeam of the corresponding wavelength. The optical film 520 is disposedon the organic light-emitting display panel 510.

The optical film 520 has a structure of the optical film 7 of FIG. 11.However, the present disclosure is not limited thereto, and theabove-described various optical films may be used as the optical film520.

The organic light-emitting display panel 510 is formed to have amicrocavity structure in order to improve brightness and color purity.That is, the organic light-emitting display panel 510 includes aplurality of organic light-emitting diodes (OLEDs) each emitting any oneof red, green, blue, and white colors. The OLED includes an anode 13, anorganic light-emitting layer 14, and cathode 15. As shown in FIG. 7, theorganic light-emitting display panel 510 includes the OLED configured insuch a manner that the unit pixel thereof displays red (R), green (G),and blue (B). The organic light-emitting display panel 510 is formed tohave a microcavity structure in which a distance between the anode 14and the cathode 15 of the red OLED, which has a long wavelength, is thelongest and a distance between the anode 14 and the cathode 15 of theblue OLED, which has a short wavelength, is the shortest. That is, theorganic light-emitting display panel 510 is formed in such a manner thatthe distance between the anode 13 and the cathode 15 matches with arepresentative wavelength of red, green, and blue. Thus, only thecorresponding light beam resonates and is emitted to the outside andother light beams are attenuated.

Hereinafter, the organic light-emitting display panel will be describedin detail.

Each sub-pixel of the organic light-emitting display panel 510 isdisposed between a first substrate 11 and a second substrate 19, whichface each other. The sub-pixel may include the OLED including the anode13, the organic light-emitting layer 14, and the cathode 15, and adriving circuit unit 12 that is formed on the first substrate 11 and iselectrically connected to the anode 13 and the cathode 15.

Here, the anode 13 may be formed of an opaque metal, such as aluminum(Al), and the cathode 15 may be formed of a transparent electrode ofoxide, such as indium tin oxide (ITO) or a semitransparent electrode ofa nickel (Ni) thin film so that light emitted from the organiclight-emitting layer 14 may easily pass therethrough.

The driving circuit unit 12 may include at least two thin filmtransistors (TFTs) (not shown) and capacitors (not shown). The drivingcircuit unit 12 controls the brightness of the OLED by controlling anamount of current to be applied to the OLED in response to a datasignal.

The driving circuit unit 12 is a circuit for driving the unit pixel ofthe organic light-emitting display panel 510. The driving circuit unit12 may include a gate line, a data line that perpendicularly crosses thegate line, a switching TFT that is connected to the gate line and thedata line, a driving TFT that is connected to the OLED between theswitching TFT and a power line, and a storage capacitor that isconnected between a gate electrode of the driving TFT and the powerline.

Here, the switching TFT applies the data signal of the data line to thegate electrode of the driving TFT and the storage capacitor, in responseto a scan signal of the gate line. The driving TFT controls thebrightness of the OLED by adjusting a current applied from the powerline to the OLED in response to the data signal from the switching TFT.In addition, the storage capacitor is charged with the data signal fromthe switching TFT and applies a charged voltage to the driving TFT, sothat the driving TFT may apply a constant current even though theswitching TFT is turned off.

The organic light-emitting layer 14 includes a hole injection layer(HIL), a hole transport layer (HTL), an emission layer, an electrontransport layer (ETL), and an electron injection layer (EIL) that aresequentially stacked on the anode 13. According to such a structure,when a forward voltage is applied between the anode 13 and the cathode15, electrons move to the emission layer via the EIL and the ETL fromthe cathode 15, and holes move to the emission layer via the HIL and theHTL from the anode 13. The electrons and the holes, which are injectedinto the emission layer, are recombined in the emission layer to therebygenerate excitons. The excitons emit light while transitioning from anexcited state to a ground state. At this time, the brightness of theemitted light is proportional to the amount of current flowing betweenthe anode 13 and the cathode 15.

In addition, the organic light-emitting display panel 510 includes colorfilters 17 in order to improve color efficiency. Here, the color filters17 are formed on the second substrate 19, wherein a red color filter isformed in a red sub-pixel area, a green color filter is formed in agreen sub-pixel area, and a blue color filter is formed in a bluesub-pixel area. If when the unit pixel is constituted by four colors(red, green, blue, and white), the color filter 17 may not be formed ina white sub-pixel area.

Although not shown in the drawing, a black matrix for reducing (or,preventing) light leakage and mixing of colors may be formed at aninterface between sub-pixels in the second substrate 19. In addition, aspacer for electrically connecting the anode 13 and the cathode 15, anda spacer for electrically connecting the anode 13 and the drivingcircuit unit 12 may be formed, and such an electrical connection may bemade by bonding between the first substrate 11 and the second substrate19 using a sealing material.

On the other hand, in the organic light-emitting display device 500employing a microcavity structure, as a viewing angle is tilted towardthe side from the front, maximum resolution wavelength becomes shorter,and thus color shift occurs as the maximum resolution wavelengthdecreases. For example, even if white color is embodied at the front,the white color may become bluish at a lateral side due to blue shiftphenomenon.

In the organic light-emitting display device 500 of the current exampleembodiments, the optical film 520 is disposed on the organiclight-emitting display panel 510 in order to reduce the color shift.

The groove GR of the optical film 520 may have an extended stripe shape.

In this case, the optical film 520 is disposed on the organiclight-emitting display panel 510 in such a manner that a longitudinaldirection of the stripe shape is a vertical (Z) direction of the organiclight-emitting display panel 510. In addition, the optical film 520 maybe disposed on the organic light-emitting display panel 510 so that ngrooves GR (where n is an integer) of the optical film 520 correspond toone pixel of the organic light-emitting display panel 510. However, thenumber of grooves GR shown in the drawing is just an example, and is notlimited thereto.

In addition, the optical film 520 includes the lens pattern region A1 inwhich the plurality of grooves GR are formed, and the non-pattern regionA2. A width S2 of the non-pattern region A2 in a horizontal direction Yis formed to be smaller than a width S1 between the adjacent pixels thatare separated from each other in the horizontal direction Y. Inaddition, a ratio of an area of the lens pattern region A1 in theoptical film 520 may be greater than an aperture ratio of the organiclight-emitting display panel.

As described above with reference to FIGS. 3 and 4, the high refractiveindex pattern layer 110 and the low refractive index pattern layer 120which correspond to the lens pattern region A1, emit light, which isincident at a constant angle, at various angles to thereby serve as acolor shift reducing layer. The light emitted from the organiclight-emitting display panel 510 has distribution of a set (or,predetermined) angle, and has color shift properties that are slightlydifferent from each other according to the angle. After the light passesthrough the color shift reducing layer including the high refractiveindex pattern layer 110 and the low refractive index pattern layer 120,a light beam incident on the color shift reducing layer at an angle witha small color shift and a light beam incident on the color shiftreducing layer at an angle with a large color shift are evenly mixed andare then emitted, and thus the color shift is reduced according to aviewing angle of a viewer.

In addition, the non-pattern region A2 reduces image blur that may occurdue to the optical film 1.

When the width S2 of the non-pattern region A2 is set to be excessivelylarge, the degree of a reduction in color shift, which is an intendedfunction of the optical film 520, may deteriorate. In addition, when thewidth S2 of the non-pattern region A2 is set to be excessively small,image blur may occur as described above with reference to FIG. 5. Thus,the width S1 and the width S2 are required to be appropriatelydetermined.

FIG. 23 is a simulation graph illustrating image blur (blur intensity)and color shift of the degree of a reduction.

The degree of blur is represented by a relative ratio of luminanceintensity of blur occurring at an intermediate point between pixels. Asthe relative ratio increases, the image blur increases.

The color shift uv represents the degree of color shift at a viewingangle of 60 degrees, on the basis of a front white (x, y)=(0.28, 0.29)color. As the value of the color shift at a viewing angle of 60 degreesis reduced, the color shift according to the viewing angle is excellent.In general, when the color shift is less than approximately 0.02, thecolor shift is not likely to be recognized by human eyes.

Referring to the graph, as the S2/S1 decreases, the image blur isreduced, but the degree of improvement of the color shift is decreased.On the contrary, as the S2/S1 increases, there is an advantage in termsof the improvement of the color shift, but the excessive degree of theimage blur occurs. Such a tendency is maintained according to alight-emitting property, but an absolute value may vary. An appropriaterange of the S2/S1 may be set in consideration of the degree ofimprovement of the color shift and the degree of the image blur.

In FIG. 22, R, G, and B pixels are shown to have the same size. However,this is just an example, and the sizes thereof may be adjusted accordingto the brightness of the pixels. In addition, the shapes of the pixelsmay vary.

In addition, it is shown that a longitudinal direction of the groove GRis consistent with a vertical direction Z of the organic light-emittingdisplay panel 510. However, the longitudinal direction of the groove GRmay be inclined at a set (or, predetermined angle) with respect to thevertical direction Z of the organic light-emitting display panel 510 inorder to reduce the likelihood of (or, prevent) a moire pattern frombeing generated.

The above-mentioned optical film refracts light that is incidentobliquely and light that is incident perpendicularly, in variousdirections including a direction toward a front and a direction toward aside, and emits the light.

Therefore, in an organic light-emitting display device employing theabove-described optical film, an organic light-emitting layer may beformed to have a microcavity structure in which color purity isimproved. At this time, color shift according to a viewing angle may bereduced, and thus a high-quality image may be provided.

In addition, in the above-mentioned optical film, when the optical filmincluding a lens pattern region and a non-pattern region which arealternately formed is attached onto a display panel, the non-patternregion is formed to correspond to at least a part of a non-emissionregion of the display panel, thereby allowing image blur to be reduced(or, minimized).

It should be understood that the example embodiments described hereinshould be considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features within each embodiment shouldtypically be considered as available for other similar features in otherexample embodiments.

1. (canceled)
 2. An optical film, comprising: a high refractive indexpattern layer including a lens pattern region and a non-pattern regionalternately formed, wherein the lens pattern region includes a pluralityof grooves and flat surfaces between each of the plurality of grooves,and the non-pattern region has no pattern; and a low refractive indexpattern layer formed of a material having a refractive index smallerthan a refractive index of the high refractive index pattern layer,wherein the low refractive index pattern includes a plurality of fillingportions filling the plurality of grooves, wherein light is incident tothe optical film through the low refractive index pattern layer and isemitted through the second surface of the high refractive pattern layer.3. The optical film of claim 2, wherein the lens pattern region has awidth larger than a width of the non-pattern region.
 4. The optical filmof claim 2, wherein the low refractive index pattern layer furtherincludes a flat film having a set thickness, and the flat film connectsthe plurality of filling portions.
 5. The optical film of claim 2,wherein the low refractive index pattern layer is formed of a resinmaterial.
 6. The optical film of claim 2, wherein the plurality ofgrooves each have an extended stripe shape.
 7. The optical film of claim2, wherein the plurality of grooves each have a dot shape in aperspective view with respect to the high refractive index patternlayer, and a parabolic shape in a cross-sectional view with respect tothe high refractive index pattern layer.
 8. The optical film of claim 2,wherein the optical film is on a display panel having an arrangement ofpixels, the arrangement of pixels including an emission region and anon-emission, region alternately formed, wherein the lens pattern regionfaces the emission region; and wherein the lens pattern region and thenon-pattern region are arranged so that the non-pattern region faces atleast a part of the non-emission region.
 9. The optical film of claim 8,wherein the lens pattern region has a width larger than a width of theemission region.
 10. The optical film of claim 2, further comprising: ananti-reflection film on the high refractive index pattern layer; and afirst adhesive layer under the low refractive index pattern layer. 11.The optical film of claim 10, further comprising: a first base layerbetween the high refractive index pattern layer and the anti-reflectionfilm.
 12. The optical film of claim 11, further comprising: a circularpolarization film between the high refractive index pattern layer andthe anti-reflection film, the circular polarization film including aphase shift layer and a linear polarization layer.
 13. The optical filmof claim 12, wherein the first adhesive layer, the low refractive indexpattern layer, the high refractive index pattern layer, the phase shiftlayer, the linear polarization layer, the first base layer and theanti-reflection film are sequentially arranged.
 14. The optical film ofclaim 10, further comprising: a phase shift layer, a linear polarizationlayer, and a first base layer, wherein the first adhesive layer, thephase shift layer, the linear polarization layer, the first base layerand the low refractive index pattern layer are sequentially arranged.15. The optical film of claim 10, further comprising: a transmittanceadjusting layer between the high refractive index pattern layer and theanti-reflection film.
 16. An organic light-emitting display device,comprising: an organic light-emitting display panel including aplurality of pixels and an organic light-emitting layer, wherein theplurality of pixels each emit light beams having different wavelengths,and the organic light-emitting layer has a microcavity structureconfigured resonate and emit a light beam of a corresponding wavelength;and the optical film according to claim 2 on the organic light-emittingdisplay panel.
 17. The organic light-emitting display device of claim16, wherein the plurality of grooves each have an extended stripe shape.18. The organic light-emitting display device of claim 17, wherein theoptical film is arranged on the organic light-emitting display panel insuch a manner that a longitudinal direction of the extended stripe shapeis in a vertical direction of the organic light-emitting display panel.19. The organic light-emitting display device of claim 18, wherein awidth of the non-pattern region of the optical film in a horizontaldirection is smaller than a distance between the plurality of pixelsseparated from each other in the horizontal direction.
 20. The organiclight-emitting display device of claim 16, wherein a ratio of an area ofthe lens pattern region in the optical film is greater than an apertureratio of the organic light-emitting display panel.
 21. The organiclight-emitting display device of claim 16, further comprising: a firstadhesive layer between the organic light-emitting display panel and thelow refractive index pattern layer; and an anti-reflection film on thehigh refractive index pattern layer.
 22. The organic light-emittingdisplay device of claim 21, further comprising: a circular polarizationfilm or a transmittance adjusting layer between the high refractiveindex pattern layer and the anti-reflection film, the circularpolarization film including a phase shift layer and a linearpolarization layer.